How Do Cell Phones Work?
Recently published reports* indicate that a whopping 95% of Americans own some kind of a cell phone. Of those cell phones, 77% are smartphones. Innovation and culture have been responsible for the growth of cell phone technology but we should all thank Mr. Alexander Graham Bell for introducing the first working telephone to the world in 1885. Here are some more mind-blowing statistics:
With numbers like these, it is hard to imagine our world without them. But how many of us really know how these pocket-sized marvels of technology work?
Just like the walkie-talkie you grew up with, inside every cell phone is a transmitter for sending information, a receiver for receiving information, and an antenna which helps the information travel. Like walkie-talkies, cell phones use radio waves to send signals from one device to another. The similarities between the two ends about there.
At the heart of cellular communication is the cell tower. Cell towers, as unsightly as they are, consist of a tall tower with antennas mounted in such a way that they produce hexagon-shaped areas of service coverage.
At the bottom of every tower is a series of large boxes which contain switching equipment, GPS devices and lots of electrical power sources. The hexagon-shaped service areas touch each other to form a cell-like pattern which is where the term “cellular” comes from.
Your phone always knows where the nearest tower is and connects to it automatically. The strength of your connection to the tower is represented by the bars on your cell phone. When you place a call, your cell phone sends a signal to that tower which then tracks down the landline or cell phone you are calling. The call switching equipment then assigns a unique radio frequency channel to your call and acts like a switchboard operator to patch the call through. Assigning a unique frequency channel to every call ensures that you won’t hear other voices on your call and vice-versa. As you speak into the cell phone your voice is converted to digital data and the transmitter sends that data through your antenna along radio waves to the antenna on the cell tower. The cell tower then sends the call data down to the switching equipment which then sends it to either a landline switching center through cables or to the cell tower that the receiving cell phone is connected to. That tower sends your voice data to the antenna of the receiving phone and that receiver converts it back to sound. As you move away from your cell tower, the call is automatically and seamlessly handed off to the next closest tower so that you stay connected to your call. Of course, through the magic of technology, all of this happens in fractions of a second and tens of thousands of times per call. Sometimes the process fails and that is when you experience a dropped call.
In its infancy, cell phones required the use of a heavy brick-like device with a huge antenna connected to a wire that ran into a communications device the size of a briefcase. All it did was make phone calls. Today manufactures squeeze tons of cutting-edge technology and services into a pocket-sized device that could easily rival a desktop computer. As we marvel at how quickly this technology has progressed over the years, we should also recognize the impact it has had on our daily lives. Cell phones have become our main sources of communication, news, shopping, banking, photography and videography, entertainment and of course, taking great selfies!
*Source: Pew Research Center
